Question

the atlantic cod was once the mainstay of the united states fishing industry. however, warming of the ocean along the shores of new england has caused the stock of cod to disappear almost completely. according to scientists at the gulf of maine research institute, the gulf of maine is heating up faster than a majority of the rest of the planet’s oceans. as a result of warmer ocean waters, female cod produce fewer offspring, and these fish are less likely to survive to maturity. even though recreational cod fishing was banned in 2014, and strict limitations were placed on the number of fish commercial fishermen could catch, these measures have not been enough to protect the cod. what is the main, or central, idea of the passage? because the gulf of maine is warming unusually quickly, atlantic cod are disappearing. because cod used to be abundant in the atlantic, it was once the backbone of the u.s. fishing industry. female cod are producing fewer offspring in the gulf of maine.

Explanation:

To determine the main idea, we analyze each option:

• Option 1: Talks about Gulf of Maine warming and cod disappearance, but the passage also covers the fishing industry's history with cod and conservation efforts, so this is not the main idea.
• Option 2: The passage starts by stating "The Atlantic cod was once the mainstay of the United States fishing industry" and explains the cod's abundance in the past, which aligns with the central theme of cod's importance to the US fishing industry.
• Option 3: Focuses on female cod's offspring, which is a detail, not the main idea.

Answer:

B. Because cod used to be abundant in the Atlantic, it was once the backbone of the U.S. fishing industry.